3,438 research outputs found
Editorial – Musculoskeletal pain: Which role for tapentadol?
Chronic pain is defined as pain persisting after healing of an underlying pathology or as persisting
pain in the absence of tissue damage. In the last decade, the understanding of mechanisms involved in
chronic pain led to an improved approach to patient management, with the aim to reduce discomfort,
improve quality of life (QoL) and enhance functional recovery.
Chronic musculoskeletal pain, which is frequently encountered in clinical practice, can affect patients
of all ages and is particularly common in older patients. Indeed, low back pain is the most frequent
chronic pain condition worldwide, with a lifetime prevalence of >70% in western countries1,2. Neck pain
is also a common disabling disease, with a prevalence of 23%, and is associated with high costs for medical visits and physiotherapy. Both low back pain and neck pain involve nociceptive and neuropathic
pain mechanism
1D Seismic Response Analysis of Soil-building Systems Including Failure Shear Mechanisms
Modelling of soil shear rupture due to an earthquake is not generally implemented in the common codes for 1D seismic response analysis. It requires the use of advanced plasticity-based constitutive models of soil, that are often neglected in practice. A good balance between simplicity and reliability can be achieved with methods based on simplified formulations of the mathematical equations and of the constitutive models. The paper presents a computer code based on this philosophy conceived, addressed and optimised to reliably model both the 'transient' seismic response ('stick' mode) and the permanent deformation mechanisms accounting for the coupled effects of deformability and strength ('slip' mode). The code can be adopted to evaluate the seismic performance of different geotechnical systems that can be reasonably approximated to a 1D problem. In the paper, the code is applied to model a soft-storey failure occurred in a framed structure heavily damaged during a strong-motion earthquake
Wave Celerity in Hydraulic Transients Computation for CIPP-Rehabilitated Pipes
[Abstract] Most of the water pipe infrastructure is outdated; therefore, frequent maintenance and repair works are required. To speed up the rehabilitation work and to have a more sustainable and efficient approach, trenchless methodologies have been developed in the last decades. One of the most cost-effective trenchless methods is the so-called Cured in Place Pipeline (CIPP) method, in which a resin-impregnated liner is pulled or inverted inside the host pipe and, when cured, it restores the old pipe structural and mechanical integrity. The aim of this study is to analyse the effects of the presence of a CIPP liner in a deteriorated pipe during unsteady flow for compressible fluids. In particular, the paper deals with a new formulation to compute the celerity of the wave which produces the overpressures, when the pipe wall is composed of both the host (old) pipe and the new liner, whose thickness depends on the required mechanical characteristics. The problem is strictly dependent on the mechanical properties of the liner. In order to obtain the new formula for celerity, the linear elastic problem for multi-layered pipes has been solved. The theoretical results have been validated by performing numerical simulation analysis using a Boundary Element model, with the software BEASY™. The resulting circumferential strain is integrated in the continuity equation, deriving the new formula to compute the wave celerity. The values of the celerity are dependent on the thickness and on the elastic properties of the liner. The behaviour of several combinations of thickness of the liner and Young’s modulus values has been studied and the results have been critically shown in the paper
- …